Scanning electron microscopes have long been used to inspect or observe semiconductor devices. Among such scanning electron microscopes, there are electron beam testers in which electrons obtained from the sample are energy-discriminated, an electric potential contrast image is created based on discriminated electrons, and inspections are performed for defects in the wiring of semiconductor devices. Japanese Patent Laid-open No. 10-313027 discloses an electron beam tester and a method of wiring defect inspection using this electron beam tester.
The above patent publication discloses a technique for judging whether a specific site of the sample is electrically isolated, by static electrification of the sample and confirmation of the extent of static charge in the electrified region.